1-cos(x)^2 doesn't simplify?

I found an ancient similar question, apperantly it used to work when at least x is not assigned. But when I try

syms x
simplify (1-cos(x)^2)

I get ans = 1 - cos(x)^2

Is there a reason for this, or is it just a bug?

Answer 1

[Cris LaPierre]

Perhaps try using the Steps name-value pair.

syms x
simplify(1-cos(x)^2,'Steps',10)

ans = 

[Tunahan Keskin]

I didn't know this existed, thank you.

[Tunahan Keskin]

This seems to not always work.

syms z phi
simplify(2*z^2*cos(phi) + 1 - cos(phi)^2 ,'steps',100)

ans = 2*z^2*cos(phi) - cos(phi)^2 + 1

[Cris LaPierre]

That is correct. It will not always simplify to what you want.